We have evaluated 20 patients and begun to clarify the range and variability of Proteus syndrome. This is crucial to the success of the project as only 1/2 of patients referred with a diagnosis of Proteus syndrome are judged to be affected by our criteria. We have begun collection of tissue and blood specimens by whole genome microsatellite screening for LOH. In addition, we have analyzed two Proteus syndrome tumors by comparitive genomic hybridization. This year we will initiate whole genome subtractive techniques as another approach to find the genomic alteration in the hyperplastic tissue.